There are a number of approaches you could use, depending upon the ISPs, the links you are using to reach them, the applications you are trying to support, and the relative importance you place on availability, load sharing, and complexity (you only get to chose two). Beyond that, you have provided insufficient information to make any reasonable recommendation other than study your options.
There is a brief overview of the various techniques available in the white papers section on my web site, you might want to start there, and use the approaches you think would fit you best to search the cisco web site (the pages cited by another poster are accessible to you, just not using the links provided). Try searching on the titles given.
After you have a better idea of what you want, post again with more specific questions (hint. your original posting is on the order of asking "I live 50 km from town, what vehicle should I buy?" The answer depends upon the availability of roads (you might need a helicopter to get there), the location (or a dog sled), what you need to transport (mail = motorcycle, groceries = passenger car, a family with 5 kids = minivan, stock for your building supply business = 18 wheeler, etc.)
If you don't have time to learn or simply want an answer, consider hiring a consultant to help you understand your needs and options.
Good luck and have fun!
Vincent C Jones
www.networkingunlimited.com
